Eye Anatomy

Learn about the different types of optical illusions, how they work, and how the brain sometimes misinterprets signals the eyes send.

Crying offers several benefits for both your emotional and physical wellbeing, including your eye health.

During sleep, your eyes cycle through stages of rapid and non-rapid eye movement. Learn about sleep cycles, plus why and how your eyes move during sleep.

Discover the different parts of the eye and how they work together to produce clear vision.

Are you curious how often you blink and why? The average teen or adult blinks 15 times per minute, meaning you probably blink about 21,600 times per day

Night vision (scotopic vision) is your natural ability to see in the dark. In low light, your pupils automatically widen to gather as much light as possible.

Tears are a mixture of water, electrolytes, proteins and oils. Learn what makes them taste salty and why some tears are saltier than others.

Squinting is common among people with blurry vision. But there are other causes too. And “squint eye” is something completely different. Here’s how to tell these conditions apart.

Click on various parts of our human eye illustration for descriptions of the eye anatomy; read an article about how vision works.

How far can the human eye actually see? Learn about how eye function, circumstances and visual acuity play a part in answering this question.

Peripheral vision is what allows you to see out of the corners of your eyes. Learn how it works, potential issues and answers to common questions.

Tetrachromacy is a type of color vision that allows some people to see colors others cannot. Learn more about this seemingly superhuman vision.

The eyes go through two growth spurts in life: once during the first two years and again during puberty.

Accommodation happens when your eyes require near vision — especially for reading. Find out why accommodation is important and how to solve near-vision problems.

Depth perception allows us to see the world in three dimensions and to judge the relative distance and movement between objects and ourselves.

Tears are a critical part of eye health. They moisten the eyes, protect them from debris and provide a release for emotions and pain.

Eye shape can mean the shape of the eyeball or the appearance of the eyelids. Learn how eye shape affects the visual system as well as appearance.

Binocular vision, or eye teaming, describes both eyes working together to form one image. Binocular vision dysfunction can occur if the eyes aren’t in sync.

Humans see color when cells in their eyes send signals to their brains. Find out how many colors you can see and why some people see more colors than others.

Eyelashes fall out as part of their normal growth cycle and usually grow back on their own. Sometimes, though, eyelash loss requires treatment or a transplant.

Visual tracking is crucial for reading and coordination. Learn how visual tracking disorders are diagnosed and exercises to enhance tracking skills.